摘  要  【目的】 硫氧还蛋白过氧化物酶（TPX）在昆虫抵御氧化胁迫中具有重要作用。本研究旨在鉴定小地老虎Agrotis ipsilon TPX基因，明确其编码蛋白质的抗氧化能力，阐明TPX基因在小地老虎不同发育期、不同组织以及在3种杀虫剂（高效氯氟氰菊酯、辛硫磷和氯虫苯甲酰胺）胁迫下的表达模式，为深入了解小地老虎TPX基因的生理功能奠定基础。【方法】 利用同源检索技术从小地老虎转录组中鉴定TPX基因，利用大肠杆菌表达重组蛋白并分析其抗氧化能力，使用实时荧光定量PCR技术分析TPX基因的表达模式，使用试剂盒检测幼虫体内H₂O₂的含量变化。【结果】 从小地老虎转录组中鉴定了1个TPX基因的cDNA序列，命名为AiTPX1。根据其编码蛋白质的结构特征，结合系统进化分析结果，确定AiTPX1属于2-Cys家族。在大肠杆菌中成功表达了AiTPX1重组蛋白，该蛋白能够显著提高大肠杆菌在氧化胁迫下的存活率（P<0.05）。AiTPX1基因在小地老虎不同发育期和不同组织中均有表达，但在蛹期和幼虫中肠中表达量最高。使用LC₅₀剂量的高效氯氟氰菊酯、辛硫磷和氯虫苯甲酰胺处理小地老虎幼虫后，幼虫体内H₂O₂含量显著升高，AiTPX1表达水平也显著上升。高效氯氟氰菊酯处理后24 h，AiTPX1表达水平为对照组的8.1倍（P<0.05），辛硫磷和氯虫苯甲酰胺处理后6 h，AiTPX1转录水平分别为对照组的6.5倍和6.0倍（P<0.05）。【结论】 AiTPX1可能具有缓解高效氯氟氰菊酯、辛硫磷和氯虫苯甲酰胺引起的氧化胁迫的功能，从而增强小地老虎幼虫对3种杀虫剂的耐受性。

Abstract  [Aim]  Thioredoxin peroxidases (TPX) plays an important role in protecting insects against oxidative stress. This study aims to provide a foundation for exploring the physiological function of the TPX gene in A. ipsilon by identifying the TPX sequence in A. ipsilon and determining the antioxidative ability of the protein encoded by the gene. The study will also investigate the expression profile of the TPX gene during different developmental stages, in various tissues, and in response to stress induced by three insecticides (lambda-cyhalothrin, phoxim, and chlorantraniliprole). [Methods]  The TPX gene was identified within the A. ipsilon transcriptome using a homology search-based method. The recombinant protein was expressed in Escherichia coli and its antioxidative ability was analyzed. The expression profile of the TPX gene was determined using reverse transcription quantitative PCR. A commercial kit was used to test the H₂O₂ content of larvae. [Results]  A cDNA sequence (designated AiTPX1) encoding putative TPX was identified from the A. ipsilon transcriptome. AiTPX1 encoded a protein belonging to the 2-Cys family based on its structural features and the results of the phylogenetic analysis. The recombinant AiTPX1 protein was successfully expressed in E. coli, significantly improving the tolerance of E. coli cells to oxidative stress. The mRNA of AiTPX1 was detected in all A. ipsilon developmental stages and tissues tested in this study, with the highest levels found in the pupal stage and larval midgut. After treatment with LC₅₀ concentrations of lambda-cyhalothrin, phoxim, and chlorantraniliprole, the H₂O₂ content of larvae was significantly increased and there was notable upregulation of AiTPX1 at the transcriptional level. [Conclusion]  AiTPX1 may enhance the tolerance of A. ipsilon larvae to lambda-cyhalothrin, phoxim, and chlorantraniliprole by alleviating oxidative stress induced by exposure to the three insecticides.